Discolored spruce (Picea sitchensis) needles
Observation by GIllian Brubaker:
I am walking at Campbell Airstrip and I think the spruce trees may have the rust growth that the Northern Climate Observer Newsletter talks about.
Robin Mulvey, Southeast Alaska Forest Pathologist with the U.S. Forest Service, writes:
It’s hard to tell from that photo because I can’t see the discolored foliage up close, but it does not look like the rust since the discoloration does not appear to be affect current-year foliage, as we see with spruce needle rust. The Cooperative Extension Service has been getting reports of discolored spruce trees in Southcentral Alaska, and I am observing the same phenomenon in Southeast as well. When foliage in the interior and lower crown becomes discolored in fall, it can be caused by foliage diseases or can simply be fall color and needle shed as the tree prepares for winter dormancy. It seems more pronounced this year than usual, probably related to the warm dry spring. In Southcentral, Rhizosphaera needle cast may be contributing to needle discoloration in some locations. In SE the warm, dry weather continued throughout the summer and into the fall, and I think this is the primary reason for pronounced fall color and needle shed. In most cases, if you imagine the tree without that discolored foliage, as if the discolored foliage had been shed, the tree still appears to have a sufficient amount of retained green foliage to be considered a healthy tree. In Southeast Alaska I have not seen elevated levels of the foliar fungi that can cause similar fall discoloration of older needle age classes. For more info on these diseases and how they can be identified, see our webpage. Hope this helps!
Comments from LEO Editors:
According to the National Weather Service, Anchorage has experienced a warm summer this year. As shown in the 2018 temperature chart for Anchorage (pictured below), temperatures were above normal for parts of July and August, reaching record high temperatures in September. In addition to the warm temperatures, the Alaska Daily News also reported that September in Anchorage was unusually dry. Erica Lujan
Observations From Members 